<!DOCTYPE html>
<style>
  div {
      width: 100px;
      height: 100px;
      background: green;
  }
</style>
<div></div>
<script>
  if (window.testRunner) {
      testRunner.waitUntilDone();
      testRunner.setBackingScaleFactor(2, function() { testRunner.notifyDone(); });
  }
</script>
